Method of increasing injection and withdrawal point in a solution mining cavity



Sept. 24, 1968 J. B. DAHMS ETAL 3,402,965

METHOD OF INCREASING lNJECTlON AND WITHDRAWAL POINT IN A SOLUTION MININGCAVITY Filed March L1, 1966 4 Sheets-Sheet 1 EFFLUENT ROCK SHALE ETC.

EXTRACTABLE DEPOSIT SOLVENT EFFLUENT EFFL UENT i SOLVENT 3 .11 ROCKSHALE ETC, 2 f

INVENTORS FIG. 7. JAMES B. DAHMS 5m 2 zap/nouns ATTORNEYS p 24, 1968 IJ. B. DAHMS ETAL 3,

METHOD OF INCREASING INJECTION AND WITHDRAWAL POINT IN A SOLUTION MININGCAVITY Filed March I1, 1966 4 Sheets-Sheet 2 u' u, g E 3 LL uJ S u :5 EO Q! INVENTORS JAMES 6.DAHM5 W20 1? .5DMOND5 BY emefliamk ATTORNEYS3,402,965 INJECTION AND WITHDRAWAL IN A SOLUTION MINING CAVITY J. B.DAHMS ETAL 4 Sheets-Sheet Sept. 24, 1968 METHOD OF INCREASING POINTFiled March 11, 1966 INVENTORS JAMES B. DAHM BYRON P. fDmOA/DS m wmATTORNEY! J. a. DAHMS ETAL 3,402,965

Sept. 24, 1968 METHOD OF INCREASING INJECTION AND WITHDRAWAL POINT IN ASOLUTION MINING CAVITY 4 Sheets-Sheet 4 Filed March ll, 1966 FIG. I!

4* "'lIIIIIIIIIII'IIIII'I'IIIIIII/I FIG] INVENTORS l v N JAMES B. DAHMS3720A! P. EOMONDS BY MW (MA ATTORNEY! United States Patent 3,402,965METHOD OF INCREASING INJECTION AND WITHDRAWAL POINT IN A SOLUTION MIN-ING CAVITY James B. Dahms, New Martinsville, W. Va., and Byron P.Edmonds, Regina, Saskatchewan, Canada, assignors to PPG Industries,Inc., a corporation of Pennsylvania Filed Mar. 11, 1966, Ser. No.533,489 15 Claims. (Cl. 299-4) ABSTRACT OF THE DISCLOSURE A solutionmining method is described in which a flexible tube is utilized toprovide a large travel path for incoming solvent and outgoing eflluentfrom a solution mining cavity. The flexible tube is attached to asolvent supply system and extended in the cavity a substantial distanceby the introduction of solvent. The flexible tube is positioned in thesolution of the cavity above the floor and below the ceiling and ispositioned substantially horizontally to both the floor and ceiling.

This invention relates to solution mining. It more specifically relatesto an improved method of introducing solvent to a desired location in asolution mining cavity.

In solution mining, one or more conduits are provided through aplurality of strata of varying composition to a subterranean deposit ofproduct minerals. By product minera is meant a mineral which it iscommercially desirable to extract. These minerals are extractable withsuitable solvents, typically aqueous media, e.g., water, acid, steam, oraqueous solutions unsaturated with respect to the product mineral.

In a typical commercial operation, a single cased bore hole is firstestablished to communicate with a product deposit. A length of tubing ofsmaller diameter than the casing is then placed internal to the 'borehole casing to communicate with the deposit. Solvent is introduced tothe deposit through the annulus between the casing (including liners orequivalent extensions of the casing) and the tubing. As the solventcontacts the deposit, it extracts extractable material therefrom therebyforming a solution filled cavity. Additional solvent is introduced tothe cavity and cavity solution is withdrawn through the tubing internalto the casing. The cavity is thereby caused to grow in size. If desired,the annular conduit may be used as the effluent conduit and theinternally disposed conduit as the influent conduit. As cavitiesincrease in size,they may be brought into communication with additionalbore holes. In that event, one or more cased bore holes may function asthe injection conduits while one or more separated bore holes functionas withdrawal conduits.

It has long been appreciated that the economics and efliciency of asolution mining cavity are improved by increasing the fluid travel pathwithin the cavity. This flow path is typically increased by increasingthe separation between the point of solvent injection and the point ofeffluent withdrawal. In the cavity which communicates with a singlecased bore hole, this separation has been limited to the verticaldistance between the injection and withdrawal points. As a practicalmatter, this distance could not exceed the height of the cavity. In acavity which communicates with a plurality of bore holes, separation ofthe injection and withdrawal points is greater but has nevertheless beenlimited by the fixed distances between bore holes. To increase the flowpath further, additional bore holes have heretofore been required.Providing additional bore holes is expensive and time consuming.

The present invention provides a simple and inex- "Ice pensive method ofgreatly increasing the fluid travel path within a solution miningcavity. The fluid travel path is increased by increasing the separationof the solvent injection point from the eflluent withdrawal point. Ingeneral, this increased separation is accomplished by providing a lengthof flexible tubing or conduit attached to the cavity end of the influentconduit. The flexible tubing is oriented in a direction with asubstantial horizontal component. Thus, solvent is delivered to thecavity at a point quite remote from the axis of the influent conduit. Tomaximize separation of the injection and withdrawal points, the flexibletube is oriented away from the withdrawal conduit.

A noteworthy characteristic of this invention is that the flexibletubing taught by the instant invention can deliver relatively freshsolvent, i.e., solvent which is unconcentrated with respect to theextractable minerals of the deposit to the extraction Surface of theformation. Thus, the dissolving power of the solvent in contact with theextractable material is enhanced. In a solution mining operation, it isoften desired to maintain a gradation of concentrations of cavitysolution, e.g., with the most concentrated solution at the bottom of thecavity. Horizontal separation of the inlet and outlet points contributesgreatly to maintaining the optimum gradation of concentrations in acavity. In addition, the capacity of a cavity to produce concentratedsolution increases exponentially as this horizontal spacing isincreased.

It is important to introduce the flexible tubes of this invention to thecavity in undamaged condition. A flexible tube can sometimes besatisfactorily introduced down a large, e.g., 10 inch, casing to acavity only a few hundred feet beneath the surface of the earth bymerely allowing it to dangle at the end of a liner or tubing run downthe casing. The flexible tubing may be weighted with a soluble material,e.g., a salt core to facilitate its entry into the cavity. Alternativelya Weight may be attached to the tube with cord or equivalent meansadapted to weaken and break upon aging or upon prolonged contact withthe cavity solution. Preferably, the flexible tube is protected bysuitable means to prevent its being damaged as it is introduced down abore hole. Illustrative of such means are the protective carryingdevices disclosed in applicants copending application, Ser. No. 533,558,filed Mar. 11, 1966 for Solution Mining Apparatus and Method andassigned to Kalium Chemicals Limited.

According to one embodiment, the tube is packed in a container or can ofthe type disclosed in the afore-mentioned copending application much asa fire hose is packed in a fire hose container. In the can is a nozzleor equivalent adapted to communicate with a supply conduit. The flexibletube is attached to this nozzle. In some embodiments, the can must alsoaccommodate a withdrawal conduit. The can desirably includes means forequilizing pressure across the nozzle as the can is lowered into acavity through a bore hole. There is a substantial opening in the canthrough which the flexible hose unfolds into the cavity. Usually theopening is provided with a hatch, typically a removable portion of thecan. In that event, the can desirably includes means for automaticallyremoving the hatch when the can emerges from the casing at the top ofthe cavity. The flexible tube is thereby freed from the can so that itcan extend into the cavity. Other suitable tube-carrying devices andother methods of introducing the flexible tube to a cavity will suggestthemselves to the skilled artisan.

The flexible conduit may be made of any suitable material. Variousplastic, e.g., polyethylene and polyvinylchloride films, snytheticfabrics, such as nylon and rayon, natural fabrics such as cotton twilland canvas, rubber or rubberized fabrics, or similar materials suitablefor making' flexible tubes or hoses may be employed. One particularlygood material for making flexible conduits has been rubber impregnatednylon fabric.

Sometimes a flexible tube tends to meander in the cavity when solvent isintroduced through it. A degree of meandering is generally acceptablebut it is often desired to deliver solvent to a chosen extraction area.Meandering of the flexible tube is greatly reduced by constructing itfrom a material with a rough surface. Additional roughness can be builtinto the tube, e.g., by providing several joints at intervals along itslength. The natural roughness of the tube together with the roughness ofthe joints helps encourage the conduit to straighten and remain straightwhen the fluid, e.g., solvent flows therethrough. Internal roughness ofthese tubes has been further increased by ad hering rubber crumb to theinside of the tube. To further decrease the tendency of the flexibleconduit to meander about the cavity, a means associated with theinjection point, typically an end device, may be employed. The enddevice may take a variety of forms and is designed to establish aresultant force operating on the tube in the direction of solvent flow.

The length and diameter of the flexible tubes which may be employeddepend on several factors, e.g., materials of construction, solvent flowvelocity and cavity conditions, e.g., density of the cavity solution andflow currents in the cavity. In general, flow rates are rarely highenough to utilize satisfactorily tubes larger than 6 inches in diameter.Tubes less than 2 inches in diameter are generally structurally unstableand tend to meander unduly in the cavity. Tube lengths up to severalhundred feet are possible. Three to four inch diameter tubes 30 to 100feet in length are readily employed. The tube lengths and diametersherein disclosed are by way of illustration only and are not intended tolimit the scope of the invention in any way.

The invention will be more readily understood with reference to the.drawings of which FIGURES 1, 2 and 3 illustrate a typical sequence inthe ractice of the instant invention. FIGURES 4, and 6 illustrate theoperation of a preferred carrying means or can for introducing theflexible tubes of this invention to a cavity. FIGURE 7 illustrates analternative can apparatus. FIGURE 8 illustrates a can employable in abore hole which houses a single fluid-carrying conduit. FIGURES 9, and11 illustrate various end devices useful as aids to straighten out theflexible tube and reduce the tendency for the extended tube to meander.

Referring to FIGURE 1, a cased bore hole 1 is provided to communicatewith an extractable deposit. Tubing 2 is disposed internal to the casing1 to provide a second conduit through the bore hole. Solvent isintroduced through the annular conduit 3 and efliuent (solution ladenwith extracted material) is withdrawn through the internally disposedtubing 2. In this fashion, a cavity 4 is developed.

Mineral or petroleum oil is often provided to the cavity to form aninsulating layer 5 at the top of the cavity as the cavity is developed.In this fashion, horizontal development of the cavity is encouraged.Rapid horizontal development of the cavity may be additionallyencouraged, particularly when the cavity is small, e.g., less than about50 feet in diameter, by providing a flow divertor at the base of thecasing 1. The flow divertor imparts a horizontal component of velocityto the solvent entering the cavity. The flow divertor illustratedcomprises a liner 6 attached to the tubing 2. The annulus between theliner and the casing is blocked with packing means 7. One or more holes,orifices or jets 8 are provided in the liner oriented in the desireddirection. Often a single port 8 is provided and is oriented toward asecond cavity remotely located in the same extractable deposit.

After a cavity has developed sufliciently in the desired direction toaccommodate an extended length of flexible conduit, the flow divertor isremoved from the bore hole. Flexible tubing is then introduced to thecavity as an extension of the influent conduit (see 19, 29 and 39 ofFIGURES 2 and 3). In this fashion, the injection point of the solvent isprovided at a point remote from the withdrawal point. In addition,because fresh solvent is introduced at a selected point in the cavity,the cavity is caused to develop preferentially in a desired direction.

Referring to FIGURE 2, two separated cased bore holes 11 and 21communicate with an extractable mineral deposit. Cavities 14 and 24 arethen established at the base of the bore holes in accordance with wellknown solution mining techniques, such as those previously describedherein. After each cavity has reached a suitable radius, for example, 50feet, flexible tubes 29 and 19 are introduced down cased bore holes 11and 21, respectively, by means of carrier assemblies and 30. Theflexible tubes 9 and 19 are oriented to develop the cavities toward eachother. It is often desirable to withdraw the carrier assemblies fromtime to time to replace a flexible tube with a longer flexible tube.Best results are usually obtained when the solvent injection point isclose to the extraction surface.

According to the embodiment of FIGURE 2, each carrier assembly has twofluid carrying conduits, one of which communuicates with the withdrawalconduit and the other of which communicates with the input conduit ofthe cased bore hole in which it is positioned. In FIG- URE 2, thewithdrawal conduit of carrier assembly 20 communicates with tubing 12and the annulus 13 with the input conduit (flexible tube 19) throughliner 20' which forms a part of the carrier can. The annulus betweenliner 2i) and casing 11 is blocked with packing means 17 to divertsolvent to the carrier influent conduit. Carrier assembly is of analternative type wherein the withdrawal conduit communicates with theannulus between tubing 22 and tubing 30'. Internal tubing 22communicates with the influent conduit of the can 30. Tubing 30' couldalternatively extend only part way up the casing 21 and be packed Offthe same as liner 20 is packed to casing 11.

When a relatively large cavity communicates with a plurality of casedbore holes, the flexible tubes of this invention are useful in furtherdeveloping the cavity. For example, referring to FIGURE 3, after twocavities have been brought into communication, the internal piping canbe removed from one of the bore holes 41 communicating with theresulting cavity 34. This bore hole 41 then functions as the withdrawalconduit. Flexible tube 39 may be oriented in a direction away from thewithdrawal bore hole 41 to develop the cavity further in that directionand to increase the separation between the inlet and withdrawal pointsin the cavity.

Flexible tube 39 may be the tube used to develop. the cavity initially.Often this tube is ultimately replaced by a different tube in a can 40adapted to communicate with the influence conduit only (see FIGURE 8).Of course, the flexible tubes may be removed from bore hole 31 andintroduced down bore hole 41 if it is desired to develop the oppositeend of the cavity. As the cavity increases in size, the carrier assemblycan be brought to the surface of the earth from time to time to replacethe flexible tube with a flexible tube of greater length. In removingthe carrier assembly from the cavity, the flexible tube is sometimessheared from the carrier assembly by the casing. The loss of this tuberepresents a negligible expense, however, in comparison to the economicadvantages obtained by the practice of this invention.

Although many devices and methods for introducing the flexible tubes ofthis invention to a solution mining cavity will be suggested to theskiled art, FIGURES 4 through 6 and FIGURES 7 and 8 illustrate preferreddevices.

Referring to FIGURE 4, a length of flexible tubing is shown packedinside carrier can 51. The can assembly is contained inside a bore holecasing 52. The flexible tube is packed inside the can like a fire hoseor in a snake wise fashion. The flexible tube is attached to a nozzle 53which communicates with a chamber 54 adapted to communicate with supplytubing 55. The fluid passage 56 for withdrawal from the cavity isprovided by plate 57 placed as a chord in the back of the can. Thisfluid passage connects with the annulus 58 external of tubing 55. Anopening is provided in the can. This opening is closed by hatch 59 whichin this instance is a portion of the can adapted to be removable fromthe can when it enters a cavity. The hatch is removably fixed at thebottom of the can by pegs 60 which fit into holes 61. The hatch may bebiased for removal by a spring or equivalent means (not shown) althoughthe bias of the packed tube is often sufficient to remove the hatch(FIGURE 5). A threaded or equivalent portion 62 is provided at thebottom of the can in communication with fluid passage 56. An extension63 of chosen length can be attached to this portion. The extensionlocates the withdrawal point at the desired depth in the cavity. Thispoint can be relocated from time to time by replacing the extension withan extension of a different length. A ball valve 64 or equivalentpressure relief means is provided to allow equalization of pressureacross nozzle 53 thereby avoiding rupturing of the flexible tube bytransient pressures which may arise when the can is introduced down thecasing. The annulus 67 between the can and the casing is blocked withpacking means 65, e.g., packing cups, expandable or inflatable packersor equivalent means. Because the external diameler of the can 51 is onlyslightly smaller than the internal diameter of the casing 52 an endportion 66, sufficiently reduced in diameter to accommodate the packingmeans 65, is provided.

FIGURE 5 shows the operation of the release of the hatch 59. The carrierassembly has been dropped sufficiently below the casing to allow thehatch to fall free. Prior to being introduced to the top of the cavity,the biased hatch is held in contact with the can by casing 52. Thefrictional pressure of the casing holds the hatch over the flexible tubethereby protecting it. After the hatch has fallen free, fluid pressure,usually provided by the introduction of solvent, causes the flexibletube to extend horizontally as shown in FIGURE 6. Solvent is injecteddown tubing 55 into chamber 54 and through the nozzle 53 to the flexibletube 50. Etfluent flow is into the extension 63 through the passage 56in the carrier assembly to the annulus 58 (FIGURE 4).

FIGURE 7 shows a less preferred but highly satisfactory alternativedesign of a carrier assembly for the introduction of a flexible tube toa cavity. The flexible tubing 70 is packed in the same fashion as in thecan illustrated in FIGURE 4 through 6. Nozzle 73 communicates withchamber 74 which extends beyond packing means 72. Tubing 75 extendsthrough the entire can. This apparatus is introduced through a casingand hatch 76 is removed in a fashion similar to that described inconnection with FIGURE 4 through 6. In this apparatus, however, solventflow is from the annulus above the packing 72 through chamber 74 and thenozzle 73 into and through the flexible tube 70. Cavity solution iswithdrawn through the tubing 75.

Transient pressures across the flexible tubing may be relieved duringintroduction of the apparatus shown in FIGURE 7 by any convenient valvemeans. Many such valves, e.g., sleeve valves, are known to the art. Thevalve (not shown) provides communication between the annulus or thechamber 74 and tubing 75 while the can is being introduced down a borehole. When the can is in position, the valve is closed in response tomechanical manipulation or electrical impulse. The valve may also closein response to the removal of hatch 79. Pressure relief may also beaccomplished by employing an expandable packer as the packing means 72.If the packer is left contracted until the can is in proper position,the transient pressures are often inconsequential thereby eliminatingthe need for a pressure relief valve.

Simpler carrier assemblies are employable in a well developed cavitycommunicating with a pluralitly of bore holes (FIGURE 3). When separatebore holes are used as introduction and withdrawal conduits, only onefluid-carrying conduit need be provided in association with the carrierassembly. The elimination of one of the conduits from the interior ofthe assembly makes it possible to pack a much longer tube of a givendiameter in the can. An enlarged view of such a carrier assembly isillustrated in FIGURE 8. The can 40 of FIGURE 8 need not be attached totubing when it is emplaced. It is preferably suspended from the interiorof a casing by packing means (FIGURE 3). By eliminating theconcentrically disposed tubing from a bore hole, the flow rate of fluidspassed through the bore hole can be increased. This increased flow ratefacilitates the extension of flexible tube 39.

It is, of course, recognized that the invention is operable with anynumber of equivalents to the introduction systems depicted in theseveral drawings. The drawings are for the purpose of illustratingpreferred embodments only and should not be taken as limiting theinvention in any way.

According to certain preferred embodiments of this invention, steps aretaken to encourage the flexible tube to assume a relatively stableorientation in the cavity. Sometimes it is acceptable for the tube tomeander about the cavity provided solvent is injected at a point wellremoved from the withdrawal point. More often, it is desired that thetube straighten along its full length and remain oriented in a selecteddirection. A tapered flexible conduit having a smaller diameter at theterminal and (injection point) than at the supply nozzle has lesstendency to meander than an equivalent untapered flexible tube.

FIGURES 9 through 11 show several end pieces designed to help maintain adesired orientation of a flexible tube. The device of FIGURE 9 is arigid circular plate attached to flexible tube '81 by means of straps82. Two types of enclosures 85, 86 for the flexible tube 81 areillustrated in FIGURES 10 and 11, respectively. These closures may be apart of the tube or they may be made from more rigid materials andattached to the tube. A plurality of small ports 87 are provided behindthe closed tube end for solvent flow. A number of other devices will besuggested by this disclosure to the skilled artisan.

According to another embodiment of this invention, the flexible conduitis coated, prior to packing in the carrier assembly, with a pliable orflexible material which cures or hardens to a rigid condition after theflexible tube has beenextended in the cavity. In this fashion, a rigidconduit is formed in situ in the cavity. Besides eliminating thetendency for the conduit to meander, this embodiment provides a methodof introducing a lateral extension of the withdrawal conduit to acavity. Thus, a properly treated flexible conduit can be introduced tothe cavity and extended in the usual manner. After the coating orimpregnating material has set to a rigid state, the lateral conduit ispositioned to locate its terminus at the desired withdrawal point. Byextending such a conduit in the opposite direction from the injectionconduit, the operating efficiency and economy of a solution miningcavity are even further enhanced.

Suitable materials for impregnating a flexible tube in accordance withthis embodiment include resinous materials such as polyester resinswhich can be gelled to a flexible state and which are subsequently curedto a rigid state. For example, an unsaturated polyester monomer, e.g.,propylene maleate or propylene maleate phthalate is mixed with styreneand a peroxide catalyst, e.g., benzoyl peroxide, in standardproportions. An accelerator, e.g., stannous chloride is added to speedformation of a gel. The flexible tube is coated or impregnated with thisgel and introduced to a solution mining cavity. The tube is extended inthe usual manner as taught by this disclosure.

Upon aging, the partially polymerized (gelled) mixture continues to cureuntil the gel transforms into a rigid polymer thereby rendering the tubeless flexible. As the tube becomes more rigid, it has less tendency tomeander. The effective length of the tube may actually'be extended inthis fashion. The cure of the resin can be accelerated by pumping hotflui-d, e. g., water through the extended tube. Eventually the tubebecomes quite rigid and possesses adequate strength to remain extendedeven when the direction of fluid-flow is reversed therein.

Suitable coating or impregnating materials include those which remainpliable until exposed to aqueous media, e.g., polyurethanes. Organopolysiloxanes, which cure in the presence of water to become rigid, arehighly desirable materials. Many other materials particularlypolymerization systems will suggest themselves to the skilled art.Often, when a polymer with satisfactory cured strength properties isselected, the flexible tube may be constructed of materials withrelatively less strength or durability than would otherwise be required.

According to one embodiment, resinous material such as gelled polyesteror uncured epoxy resin is introduced to a can in which a flexible tube,such as a canvas or Fiberglas tube is packed. The can is introduced downa bore hole with the resin in contact with the fabric of the flexibletube. By the time the tube is extended in a cavity, it is well treatedwith the resin. Uncured epoxy resins are particularly useful in thisembodiment. For example, approximately equal portions of an epoxy resinand a polyamide resin are introduced to a can packed with a flexibletube. The cure rate (pot life) of the mixture is selected to provideample time for the tube to be extended before the resin sets.

To avoid premature hardening of the resins used to treat the flexibletubes of this invention, a plasticizer can be included in theformulation. A plasticizer which is readily extracted from the resin bythe cavity solution is especially desired. As the plasticizer isextracted, the extended tube becomes more rigid. In other embodimentssuitable coating or impregnating material is pumped to the extendedflexible tube through the supply conduit.

Collapsable mechanical means, e.g., hinged splines, which pack with thefolded tube in the can and lock into straightened position when theflexible tube is extended are also within contemplation.

According to some embodiments, a plurality of flexible tubes areprovided at the base of a single bore hole attached either to individualor common supply conduits.

Although this invention has been described with particular reference tocertain preferred embodiments, it is not intended to limit the inventionto the details of these embodiments except to the extent that suchdetails are incorporated in the appended claims.

We claim:

1. In a solution mining operation wherein solvent is introduced througha conduit to a cavity situated adjacent extractable minerals and cavitysolution is withdrawn from the cavity through a second conduit theimprovement comprising introducing a flexible tube attached at one endto one of said conduits, feeding fluid through said attached conduit andflexible tube to extend said flexible tube a substantial distance intosaid cavity from said one end, thereby increasing the separation of theintroduction and withdrawal points in the cavity and maintaining saidflexible tube substantially horizontal with respect to the cavityceiling and the cavity floor and spaced between the ceiling and thefloor in the cavity solution.

2. The improvement of claim 1 wherein the named conduits both extendthrough the same bore hole and the conduit to which the flexible tube isattached is used as an influent conduit while the other conduit is usedas a withdrawal conduit.

3. The method of claim 1 wherein the flexible tube is adapted to becomerigid after it is extended.

4. The method of claim 3 wherein after the flexible 8 tube becomes rigidit is employed as a withdrawal conduit.

5. The method of claim 1 wherein the flexible tube is adapted internallyto offer frictional resistance to fluid passing therethrough so that thetube tends to straighten out when fluid is passed through it.

6. The method of claim 1 wherein means are provided in association withthe injection point at the end of the flexible conduit to be contactedby the solvent thereby establishing a resultant force acting upon thetube in the direction of solvent flow A 7. The method of claim 1 whereinthe flexible tube is oriented away fromthe second named conduit.

8. The method of claim 1 wherein a plurality of flexible tubes areprovided in communication with the same conduit.

9. In a solution mining operation wherein solvent is injected through aconduit to a cavity situated adjacent extractable minerals and cavitysolution is withdrawn from the cavity through a second conduit theimprovement which comprises providing a flexible tube treated with aresinous substance in at least a partially uncured state and attached atone end to one of said conduits by means adapted to orient the flexibletube in a direction with a substantial horizontal component when theflexible tube is extended, feeding fluid through said attached conduitand said flexible tube to extend said flexible tube before the cure ofsaid resinous substance is complete thereby increasing the separation ofthe injection and withdrawal points in'the cavity and continuing thecure of said resinous substance thereby causing said flexible tube tobecome rigid.

10. A method of solution mining which comprises providing a cased borehole through an extractable deposit, extracting said deposit to form acavity, providing through the cased bore hole to the cavity a carryingmeans, said carrying means being operably associated with a supplyconduit and containing a flexible tube attached to said supply conduitto allow flow from the supply conduit through said flexible tube,providing an effluent conduit in communication with said cavity,introducing solvent through said supply conduit and said flexibleconduit to the cavity at a flow rate suflicient to cause said flexibleconduit to extend a substantial distance intosaid cavity from saidcarrying mean-s thereby increasing the separation of the introductionand withdrawal points in the cavity while maintaining in said flexibletube a substan tially horizontal component with respect to the cavityceiling and the cavity floor to thereby space said flexible tube in thecavity solution above the floor and below the ceiling thereof.

11. The method of claim 10 wherein the effluent conduit is providedthrough the same cased hole as the supply conduit and is operablyassociated with the carrying means.

12. The method of claim 10 wherein the flexible tube is adapted tobecome rigid after it is extended from the carrying means.

13. The method of claim 10 wherein a flexible tube is also provided incommunication with the withdrawal conduit, said flexible tube beingadapted to become rigid after it has been extended.

14. A method of solution mining which comprises. pro viding a casedborehole through an extractable deposit, extracting said deposit to forma cavity providing through the cased bore hole to thecavity a carryingmeans having a fixed portion in which there is provided in operableassociation a supply conduit and a flexible tube attached to said supplyconduit to allow flow from the supply conduit through said flexibletube, a removable portion being provided for said carrying means andheld in association with said fixed portion by frictional pressure ofthe cased bore hole while-said carrying means is being introduced downsaid cased bore hole but biased to separate from said fixed portion whensaid carrying mcans emerges from the bore hole into the cavity therebyopening said carrying means to permit the flexible tube to be extendedout from said carrying means, lowering said carrying means through saidcased bore hole into said cavity providing a withdrawal conduit in saidcavity, introducing solvent through said supply conduit and saidflexible tube to the cavity at a flow rate sufficient to cause saidflexible tube to extend from said carrying means in a direction with asubstantial horizontal component and withdrawing efiiuent from thecavity through said withdrawal conduit.

10 15. The method of claim 14 wherein the fixed portion of the containerincludes a withdrawal conduit.

References Cited 5 UNITED STATES PATENTS 2,745,647 5/1956 Gilmore 29952,822,158 2/1958 Brinton 299-5 X 2,903,069 9/1959 LebOUrg et a1. 166l17X 10 ERNEST R. PURSER, Primary Examiner.

